All petroleum producing wells drilled in sand formations, eventually become clogged by sand. Foam emulsion well cleanout equipment and procedures were developed for use in oil wells and are not suited for use with gas wells. Oil, particularly heavy oil, can be more than 1000 times the weight of natural gas. The pressure and volume of foam emulsion needed for effective cleaning of an oil well, would hinder rather than aid in the production of natural gas.
All attempts to adapt oil well foam emulsion cleanout methods to gas wells have, to date, proven unsuccessful. There have been so many instances of gas wells being damaged, that the industry is presently pre-mixing foam in tanks and then injecting the foam into the well under carefully controlled pressures. Working with pre-mixed foam does not permit the crew servicing the gas well to react rapidly to changes in pressure by increasing or decreasing the density of the foam.